NEWTOWN, Conn. — The day began, like all days at Sandy Hook Elementary, with the morning ritual of taking attendance.

Yellow buses rolled into the parking lot just before 9 a.m., and a dozen teachers working “bus duty” greeted them at the school’s front curb. The teachers marked off students as they descended from their buses, patting their heads and counting them out loud. Then the group entered en masse through the glass doors at the front of the school and dispersed into classrooms, where the students were counted again.

Kindergartners snatched their colored name tags off a classroom wall and dropped them into a bucket so their teacher could see which ones were missing. First-graders seated in classrooms near the school’s front entrance listened for their names, raised their hands one by one and said, “Here.”

Inside a single-story school building in the quiet hills of central Connecticut, everyone was accounted for. The glass doors were locked, and the video security system was enacted. A voice came over the loudspeaker to read the Pledge of Allegiance and then the school’s daily announcements. It was the seventh day of Hanukkah. The cafeteria would serve homemade pizza and broccoli for lunch. Christmas cookies were for sale after school in the lobby.

No place is immune in the modern history of mass shootings in the United States, and this time it was Sandy Hook — where children stuff their backpacks into wooden cubbies and dress in mismatching outfits for Wacky Wednesdays, where Big Bird and Elmo run the haunted house in the gymnasium each Halloween, where a metal sign near the entrance reads, “Visitors Welcome.”

Ever since the school’s founding in 1957, its students have abided by a simple motto: “Think you can. Work hard. Get smart. Be kind.” Then, in 2010, the school hired an energetic new principal, a woman who sometimes sat cross-legged with students on the floor, and she added another clause: “Have fun.”

The mass shooting at Sandy Hook Elementary unfolded in many ways, and in many voices.

There was the language of the state police investigation report: “On 12/14/12, at approximately 9:30 a.m., Newtown Police received a 9-1-1 call reporting a possible shooting at the Sandy Hook Elementary School located at 12 Dickenson Drive in Newtown.”

There was the language of emergency radio traffic: “Units responding at Sandy Hook School. The front glass has been broken. We’re unsure why.”

But, most of all on Friday, there was the simple and uncomplicated language of an elementary school, where, at 9:35 a.m., an unfamiliar voice could be heard shouting over the loudspeaker:

“Put your hands up!”

Then came popping sounds and screams. Children ducked under their desks. Adults locked doors, turned back to face their students and wondered how to explain the unexplainable.

‘It’s a drill’

In the library, three faculty members heard the noises and hustled about 15 students toward a storage closet in the library, which was filled with computer servers. “Hold hands. Be quiet,” one teacher told the kids. One child wondered if pots and pans were clanging. Another thought he heard firecrackers. Another worried an animal was coming to the door.

They were children in a place built for children, and the teachers didn’t know how to answer them. They told them to close their eyes and to keep quiet. They helped move an old bookshelf in front of the door to act as a makeshift barricade. They wondered: How do you explain unimaginable horror to the most innocent?

“It’s a drill,” said a library clerk named Mary Anne Jacobs.

Drills they knew. Drills they understood. Their last one had been just a few weeks earlier, in mid-October, on a clear day when the children marched out of school in ordered fashion, placing their hands on each other’s shoulders to form a conga line, everyone’s eyes shut except for the designated “locomotive,” an adult at the front of the line. They had stood in the parking lot in straight lines that were never quite straight, until their teachers took attendance and marched them back inside. The drill had lasted about 25 minutes.

But now the popping sounds over the loudspeaker continued, and nobody in the library storage room thought it was safe to march outside. Jacobs decided the students needed a distraction. She found scraps of paper and some crayons on the floor of the closet, and helped pass them out. As muffled screams continued over the loudspeaker, 18 fourth graders began to color.

Near the front of the school, Victoria Soto was also trying to keep her students calm. The 27-year-old teacher hurried her first-graders into a bathroom near Classroom 10, just beyond the school’s main glass doors. Two students stood on the toilet. Others huddled on the floor. With no space left, Soto stepped out of the small room herself, a witness said. A 20-year-old man wearing black stepped into the classroom and shot her before quickly exiting the room.

“She got those kids to a good place and then told them they were safe,” said Robert Licata, the parent of one of those first-graders who survived. “She knew them well enough to make them feel okay.”

Others did the same. Music teacher Maryrose Kristopik barricaded her students in a classroom and blocked the door with xylophones. First-grade teacher Janet Vollmer read her kindergartners a story. Art teacher Virginia Gunn told her class to be quiet and used her cellphone to call police.

Caitlin Roig, a 29-year-old teacher, told ABC News that she turned the lights off in her classroom and tried to explain the situation to her first-graders. “There are bad guys out there now,” she said. “We need to wait for the good guys.” The students whispered in the room, speculating about their Christmas presents and wondering if they could defeat the bad guys with karate. One of them began to cry. “Show me your smile,” Roig told him.

“I’m thinking, as a 6-year-old, 7-year-old, what are their thoughts?” she said. “So I said to them, ‘I need you to know that I love you all very much and that it is going to be okay.’ Because I thought it was the last thing they were ever going to hear.”

Instead, they heard a knock on the door, and Roig walked closer to it. “Police!” people on the other side shouted. Roig didn’t believe them. The policemen slid their badges under the door, and Roig opened it. Some of her students walked into the hallway about 9:45 a.m., into the aftermath of a shooting.

In the language of the police report: “Teams encountered several students and staff suffering from gunshot wounds. Eighteen (18) children were pronounced dead at the scene, two (2) children were transported to Danbury Hospital and later pronounced dead. Six (6) adult victims were also pronounced dead at the scene.”

In the language of the emergency radio traffic: “I’ve got bodies here.”

In the language of the Sandy Hook hallway: “Walk with a partner,” a policeman instructed. “Shield your eyes. Hold hands.”

As the students filtered out of the school, they walked past a flier on the wall that kindergartners had posted there some weeks earlier. It was an annual class prank, a Christmastime school tradition. The class had lost a gingerbread cookie in the school oven, and now they were searching for it. “WANTED,” the sign read. “Missing Gingerbread Man.” But now that sign was obscured by SWAT teams and stretchers and the harried assembling of a makeshift morgue. The students continued through the hallway, passing the security camera and exiting through the glass doors.

One complained of a stomachache. Another would later tell his father that he had wanted to “run from the school like Forrest Gump.” Another, who waited out the shooting in the bathroom, would be too scared to go to the bathroom alone at home.

The waiting

Outside the school, 17-year-old Mergim Bajraliu scanned their faces and looked for his sister, Vanessa, a fourth-grader. She had left for school in a pink jacket and jeans. Bajraliu saw one girl exit the school splattered with blood. He saw two more, their bodies limp and their faces pale, carried out by state troopers. One of them looked like his sister.

“I got close to the state trooper to get a good view,” he said. “The poor girl was not my sister.”

His mother joined him in the school parking lot. Then an uncle came, too. They waited outside as hundreds of children passed by, standing near where the bus had dropped Vanessa off for school that morning. “If I could describe it in one world, it would be ‘hell,’ ” Mergim said.

Finally, after 20 minutes, he saw her — healthy, pale, walking out of the building with her art class. She searched the parking lot for her family and then collapsed in her mother’s arms.

In the hours ahead, children would begin to ask their parents a series of difficult questions about the shooting, and parents would try to distill a tragedy in the language of childhood. “Are we safe? Is it okay? Are the bad guys gone?” said David Connors, the father of third-grade triplets.

“Are they dead? Are they in heaven yet?” said Licata, the parent of a first-grader.

One of the questions — the most simple and the most persistent, the quintessential question of childhood — would also become the most difficult:

“Why?”

But first, in the hours after the shooting, police directed students and families to a nearby firehouse, a low-slung building that was decorated with Christmas lights. Firefighters moved out their trucks to make more space for the families. In one room, parents gathered to wait for their children. In another, children gathered to wait for their parents. Cartoons played on TV, and volunteers passed out Christmas cookies and juice. A local pastor and a few school officials stepped in front of the room holding several pieces of paper. It was a printed list of children who attended Sandy Hook.

“We are going to need to take attendance,” said Robert Weiss, the pastor of nearby St. Rose Church.

And this time, so many names were unaccounted for.

Steve Vogel, Anne Hull and Colum Lynch in Newtown and Brady Dennis and Julie Tate in Washington contributed to this report.

Eli Saslow is a reporter at the Washington Post, where he covered the 2008 presidential campaign and has chronicled the president’s life inside the White House. He won the 2014 Pulitzer Prize for Explanatory Reporting for his year-long series about food stamps in America.

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